When Seattle blogger Jason Brunet first heard about the coal ash spill into Tennessee's Emory River, his mind immediately went to Chattanooga.

Mr. Brunet, a volunteer at the Seattle Aquarium, remembered an article about the Tennessee Aquarium's lake sturgeon program, where the aquarium and Tennessee Wildlife Resources Agency have reintroduced the large, ancient fish to the Tennessee River system. He was immediately concerned about how the spill might affect sturgeon.

"It looked like if you just put a bottle in the water (at the spill site), it would end up at the Tennessee Aquarium," he said.

Officials at the aquarium and wildlife agency say they release the sturgeon upstream on a different tributary of the Tennessee, but they are unsure of how the spill might affect any sturgeon who have moved downstream.

"It can't be good," said Dr. Anna George, director of the Tennessee Aquarium Research Institute.

The sturgeon are released in the French Broad River, which snakes south and west past Knoxville to join the Holston River and form the headwaters of the Tennessee River.

About 40 miles to the southwest, the Emory flows into the Clinch River near Kingston, Tenn., then meets the Tennessee River just north and east of the Watts Bar Reservoir. The Emory received part of 1 billion gallons of fly ash mixed with water that escaped from a retaining pond when a Tennessee Valley Authority dike failed on Dec. 22.

Though miles separate the release point of the sturgeon and the spill, Dr. George and others with the program know that at least 20 percent of the sturgeon head downstream as far as Watts Bar, using a canal to get around a dam.

"There's nothing stopping them from deciding they want to go downriver," said Dr. Phil Bettoli, assistant unit leader at the Tennessee Cooperative Fishery Research Unit of the U.S. Geological Survey.

Dr. Bettoli is in the midst of a routine evaluation of the sturgeon population and said it will take time to know how many of the fish were downstream of the spill and how they might be affected.

Near the spill site, several pockets of dead fish have been reported, but the TVA said the fish kills occurred when the fish were stranded on land and not because of toxic elements in the stream.

"The force of the water during the initial event stranded some fish out of the water and they subsequently died. That was not related to water quality," a TVA statement said.

"Oh really?" asked Dr. Bettoli, laughing when he heard the statement. "That's interesting."

On Friday, the U.S. Environmental Protection Agency said sediment and water samples near the spill contained high amounts of arsenic, with one sample containing more than 149 times the maximum safe level.

In a statement released earlier this week, the TVA said initial tests at all of its sampling locations show "concentrations of toxic metals were below levels established by the Tennessee Department of Environment and Conservation to protect fish and aquatic life."

Though there are plenty of variables, fish have not fared well in past coal spills, according to Dr. George. She cited a huge fish kill on the Clinch River in Virginia in 1967, where a ruptured dike allowed a large amount of similar coal ash into the water.

"Coal ash has been documented to be lethal," she said.

The river system around the spill contains two threatened or rare fish species - the spot fin chub and the ashy darter - and four mussel species that live downstream are federally monitored, according to Dr. George.

Dr. Bob Jenkins, professor emeritus at Roanoke College, described what he saw while investigating the Virginia kill 42 years ago in his book "Freshwater Fishes of Virginia."

"A glance at a backwater revealed a flotilla of bloated bodies, the wake of massive mortality that was duplicated up and down the river," his account states.

In a phone interview Wednesday, Dr. Jenkins said the threat to the sturgeon and other fish depended entirely on the volume and movement of the river system. Even in a mass kill such as the one in 1967, the longterm prognosis is fair and most of the fish species return, he said.

The recovery "began in Virginia relatively quickly," he said, and the Clinch was "excellent" in the state by 1985.

Aside from concerns about toxic chemicals, the sediment alone from the dam burst might be enough to smother the tiny invertebrates the fish feed on, according to George Scholten, reservoir fisheries coordinator for the Tennessee Wildlife Resource Agency.

"If it doesn't affect the fish, it will probably affect the critters they eat," he explained.

Mussels, a favorite food of the sturgeon, catfish, water fowl, otters, muskrats and many other fish, are particularly susceptible to pollution and sudden movements of sediment, according to Don Hubbs, mussel program coordinator with the wildlife agency.

"If a fish senses pollution, it can escape it. The problem with freshwater mussels is they can't swim away," he said.

Mr. Hubbs said he and other divers likely would head to the spill site as early as this week "to see if everything is as the agencies are saying they are" and to check on sediment build-up.

But, according to Dr. Bettoli, only time will tell the longterm affects of the coal ash and other pollutants.

"The fish in the Watt's Bar lake are already carrying a heavy load of things you wish they weren't," he said, mentioning the advisories against eating fish from the lake due to PCB, lead, arsenic and other contaminants.

"This is far more subtle," he said. "It may be a profound affect or it may just be another environmental insult."